• 제목/요약/키워드: Flux-switching

검색결과 204건 처리시간 0.031초

변압기 직렬구성을 이용한 HBML 인버터에 관한 연구 (The Study on the HBML Inverter Using the Cascaded Transformers)

  • 박성준;박노식;강필순;김광헌;임영철;김철우
    • 전력전자학회논문지
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    • 제9권4호
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    • pp.334-340
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    • 2004
  • 본 논문에서는 캐스케이드 변압기를 이용하는 멀티레벨 인버터의 변압기 크기를 동일화시키기 위한 효과적인 스위칭 패턴을 제안한다. 제안된 스위칭 방식은 기존의 SHEPWM 스위칭 방식을 기초로 하여 각 변압기에 인가되는 최대 자속을 동일하게 함으로서 캐스케이드 변압기의 위치에 상관없이 동일한 설계가 가능하다. 따라서 동일한 풀-브리지 모듈의 이용이 가능하고, 모듈화 특성을 개선시키며, 제작의 용이성을 쾌할 수 있다. 제안된 스위칭 기법의 기본 아이디어를 이론적으로 분석하며, 타당성을 실험을 통하여 입증한다.

전압벡터의 근사 전압함수를 이용한 PMSM의 DTC-PWM 제어방식 (A DTC-PWM Control Scheme of PMSM using an Approximated Voltage Function of Voltage Vector)

  • 곽윤창;이동희
    • 전력전자학회논문지
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    • 제20권5호
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    • pp.421-428
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    • 2015
  • An advanced direct torque control (DTC) with pulse width modulation (PWM) method is presented in this paper. The duty ratio calculation of the selected voltage vector is based on the voltage functions of the selected voltage vector according to the sector angle. The proposed DTC uses a conventional DTC scheme with six sector divisions and switching rules. However, the winding voltages are supplied by the PWM approach. Furthermore, the duty ratio of the switching voltage vector is determined by the flux, torque error, and motor speed. The base voltage that shall determine the duty ratio can be calculated by approximate voltage functions according to the voltage angle. For the calculation of base voltages, second-order quadratic functions are used to express the output voltage of the selected voltage vector according to voltage angle. The coefficients for the second-order quadratic functions are selected by the voltage vector, which is determined by the switching rules of the DTC. In addition, the voltage functions are calculated by the coefficients and voltage angle between the voltage vector and rotor position. The switching voltages from the calculated duty ratio can supply the proper torque and flux to reduce the ripple and error. The proposed control scheme is verified through practical experimental comparisons.

An Improved Model Predictive Direct Torque Control for Induction Machine Drives

  • Song, Wenxiang;Le, Shengkang;Wu, Xiaoxin;Ruan, Yi
    • Journal of Power Electronics
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    • 제17권3호
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    • pp.674-685
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    • 2017
  • The conventional model predictive direct torque control (MPDTC) method uses all of the voltage vectors available from a two level voltage source inverter for the prediction of the stator flux and stator current, which leads to a heavy computational burden. This paper proposes an improved model predictive direct torque control method. The stator flux predictive controller is obtained from an analysis of the relationship between the stator flux and the torque, which can be used to calculate the desired voltage vector based on the stator flux and torque reference. Then this method only needs to evaluate three voltage vectors in the sector of the desired voltage vector. As a result, the computational burden of the conventional MPDTC is effectively reduced. The time delay introduced by the computational time causes the stator current to oscillate around its reference. It also increases the current and torque ripples. To address this problem, a delay compensation method is adopted in this paper. Furthermore, the switching frequency of the inverter is significantly reduced by introducing the constraint of the power semiconductor switching number to the cost function of the MPDTC. Both simulation and experimental results are presented to verify the validity and feasibility of the proposed method.

자기회로의 위상학적 상사성을 이용한 전류제한기 구조에 관한 연구 (The Research for a Structure of Current Limiter using a Phasic Similitude of Magnetic Circuit)

  • 지근양;민경일;이수원;장봉환;문영현
    • 전기학회논문지
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    • 제58권11호
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    • pp.2128-2135
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    • 2009
  • In this paper, current limiter using a magnetic switching which is based on magnetic flux change in the case of fault is proposed. This current limiter consists of iron-core and three parts of coils. One is the primary coil connected to the power system. Another is the secondary coil wound to the opposite direction of the primary coil's winding. The other is the secondary of the secondary coil which is a movable copper plate winding and located below the secondary coil. In the normal state, the magnetic flux produced in the primary and secondary coils flows to the opposite directions each other and becomes to be canceled out. Therefore the voltages induced between the coils are zero. In the case of a fault, at the moment of a fault occurrence recognition, the switch connected to a secondary coil is opened and the secondary of the secondary coil is pulled out to the outside of the iron-core. Then, magnetic flux becomes to flow through the iron-core. Accordingly, the voltage is induced between the both ends of the primary coil and makes the current reduced. Therefore it is possible to cut off the circuit breaker easily with the proposed current limiter. This paper analyzes the current limiting effects and the detailed results are given.

일정 스위칭 주파수를 위한 유도전동기의 직접토오크 제어 (Direct Torque Control Of Induction Motor for Constant Switching Frequency)

  • 최연옥;정병호;임병옥;정삼용;서진연;조금배;백형래
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 하계학술대회 논문집 B
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    • pp.1152-1154
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    • 2002
  • In this paper, a direct torque control method of an induction motor is proposed which enables constant switching frequency. The switching strategy of a conventional direct torque control scheme which is based on hysteresis comparator results in a variable switching frequency which depends on the speed, flux, stator voltage and hysteresis band of the comparator. This paper proposes a new switching strategy which determine the effective switching time on each switching period by comparing the ascending and descending torque slopes. The simulation results are presented to verify this proposed scheme.

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고정자 자속제어를 이용한 유도전동기의 새로운 직접 토크 제어 (A Novel Direct Torque Control of Induction Motor using stator flux)

  • 박준현;정종진;최종우;김흥근
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2001년도 추계학술대회 논문집
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    • pp.15-18
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    • 2001
  • This paper describes a control scheme for direct torque and flux control of induction machines. The proposed predictive flux control scheme has directly calculated the reference voltage space vector based on flux errors in order to control the torque and flux. This proposed control scheme has not the requirement of a separate current regulator and proportional-integral (PI) control of the flux, torque, and/or current error, thereby improving transient performance and also has the advantage of less torque ripple in steady state with a fixed switching period. The effect of proposed method has been proven by simulations and experiments.

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유도전동기의 새로운 직접 토크 제어 (A Novel Direct Torque Control of Induction Motor)

  • 박준현;이경주;이득기;정종진;최종우;김흥근
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2001년도 전력전자학술대회 논문집
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    • pp.426-429
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    • 2001
  • This paper describes a control scheme for direct torque and flux control of induction machines. The proposed predictive flux control scheme has directly calculated the reference voltage space vector based on flux errors in order to control the torque and flux. This proposed control scheme has not the requirement of a separate current regulator and proportional-integral (PI) control of the flux, torque, and/or current error, thereby improving transient performance and also has the advantage of less torque ripple in steady state with a fixed switching period. The effect of proposed method has been proven by simulations.

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A Simple Sensorless Scheme for Induction Motor Drives Fed by a Matrix Converter Using Constant Air-Gap Flux and PQR Transformation

  • Lee, Kyo-Beum;Blaabjerg, Frede
    • International Journal of Control, Automation, and Systems
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    • 제5권6호
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    • pp.652-662
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    • 2007
  • This paper presents a new and simple method for sensorless operation of matrix converter drives using a constant air-gap flux and the imaginary power flowing to the motor. To improve low-speed sensorless performance, the non-linearities of a matrix converter drive such as commutation delays, turn-on and turn-off times of switching devices, and on-state switching device voltage drop are modeled using PQR transformation and compensated using a reference current control scheme. The proposed compensation method is applied for high performance induction motor drives using a 3 kW matrix converter system. Experimental results are shown to illustrate the feasibility of the proposed strategy.

계자권선형 12슬롯-10극 자속 역전식 동기 전동기의 최적 설계 (Optimal Design of Field-Excitation Flux-Switching Synchronous Machine for ISG Application)

  • 구본길;정일수;남광희
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2013년도 추계학술대회 논문집
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    • pp.23-24
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    • 2013
  • In recent years, ISG (Integrated Starter and Generator) system receives a great attention for electric electrification of normal gasoline vehicle. As a cost-effect machine design, an ISG without a permanent magnet is considered. A 12slot-10pole field-excitation flux-switching synchronous machine (FEFSSM) is designed and analyzed via JMAG. The active parts such as the field excitation coil and armature coil are located on the stator. The rotor part consisting of single piece iron makes it more robust and suitable to apply for high speed motor drive system application coupled with reduction belt. The design target is the motor with a maximum torque of 40Nm, a maximum power of 10kW and a maximum speed of 14000 rpm. In this paper, design optimization method is proposed for high torque capability.

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